I have always wondered what the heck is the difference between JScript and JavaScript. And I found this from Javascripts.faqts:

Netscape originally developed a scripting language for use in its browsers, calling it LiveScript [1]. Java being an internet buzzword at that time, for marketing reasons they renamed the scripting language to JavaScript.

Microsoft implemented its own version of JavaScript and called it JScript.

Netscape, Microsoft and others started standardizing the scripting language, using the ECMA standardizing organisation (http://www.ecma.ch) for that. Thus the language standard is now called ECMA Script.

The standard is only about the core language, with data and objects like numbers, strings, booleans, Object, Array, Function, Date, Math, but NOT about application specific objects like browser specific objects (document, window, links, images etc).

The core features of Netscape’s JavaScript and Microsoft’s JScript are pretty much compliant with the ECMA Script standard, but the application specific objects like the browser DOM (Document Object Model) and the server object model differ.